JPS62197696A - Cooling turbofan for engine - Google Patents

Abstract

PURPOSE:To reduce noise by installing an annular straightening plate in concentric form to a turbofan onto the front edge surface of each blade of the turbofan fixed at the top edge part of a rotor. CONSTITUTION:The rotor 4 of an AC generator 3 is installed at the top edge part of the crankshaft 2 of an engine 1, and a turbofan 5 is fixed at the top edge part of the rotor 4. An annular straightening plate 11 in common for each blade is installed in concentric form to the turbofan 5 at the front edge surface of each blade 10 of the fan 5. Therefore, the air stream is straightened in the centrifugal direction, and no eddy current is generated between the front edge surface of a blade and a shroud, and noise is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an engine cooling turbo fan, and particularly to a cooling turbo fan with low noise and high cooling efficiency.

[Conventional technology]

Conventionally, cooling fans for cooling the engine of a two-wheeled motor vehicle, for example, are attached to the outer surface of the rotor of an alternator that is rotated by the crankshaft of the engine, and axial flow type and centrifugal type are used.

[Problem that the invention seeks to solve]

In general, centrifugal fans (turbo fans) are advantageous in reducing noise due to their low overall thickness, but in order to obtain the same flow rate as an axial flow fan with the same diameter (exit angle of 90” or more), the fan This required an increase in the thickness (height) of the motor, making it unsuitable for scooters with small spaces.

By the way, the relationship between the fan height D and the air flow iQ is the fourth
As shown in the figure, although theoretically it is Q-D, the flow rate Q tends to decrease with respect to the height D in a scooter class (φ200 mm or less) fan.

The reason for this is thought to be that, as shown in FIG. 6, a backflow occurs between the fan and the shroud disposed in front of the fan, increasing resistance.

[Means for solving problems]

The present invention was developed with the aim of solving the above-mentioned problems and providing an engine cooling turbo fan that is compact, has high air blowing and cooling efficiency, and has low noise, suitable for vehicles with small installation spaces such as scooters. Specifically, a turbo fan is fixed to the tip of the rotor of a generator driven by the engine, and an annular rectifier plate is installed on the front end of each blade concentrically with the turbo fan to cool the engine. This constitutes a turbo fan.

[For production]

The turbo fan rotates with the rotation of the rotor to cool the area around the generator and engine. The blades of a turbo fan are installed in a radial direction from the rotation axis of the fan.
Since an annular baffle plate is attached to the front end surface of the blade in the axial direction, the airflow flows from the central hole of the baffle plate in the direction of the rotation axis of the fan, and is blown in the centrifugal direction by each blade. At this time, the rectifying plate rectifies the airflow flowing in the centrifugal direction toward the outlet, so a part of the airflow drawn in by the fan does not flow backwards, and the speed of the airflow sliding on the rectifying plate surface increases, so the airflow is It has the effect of increasing the flow rate.

The height of the blades can be lowered by the amount of air flow that increases, making the entire fan smaller.
Turbo fans that can reduce noise can be installed even in small space vehicles such as scooters.

〔Example〕

Embodiments of the present invention will be described based on the drawings. FIG. 1 is a sectional view showing the relationship between an alternator installed in an engine and a cooling turbo fan.

A rotor 4 of an alternator 3 is attached to the tip of the crankshaft 2 of the engine 1 of the vehicle, and a turbo fan 5 is attached to the tip of the rotor 4 in the axial direction 2 concentrically with the rotor 4.
It is fixed with bolt 6.

A shroud 7 is provided in front of the tip of the turbofan 5 in the axial direction 2 to cover the generator 3 and the turbofan 5, and its intake lower A is located concentrically with the turbofan 5. .

The turbo fan 5, as shown in FIGS. 2 and 3,
The base body 8 has a circular planar shape, and has a bulge portion 9 that bulges out in the shape of a mountain at the center, and a plurality of blades 10.1 arranged at equal intervals in the radial direction on the periphery of the base body 8.
0... is formed in a low oil shape that extends in the centrifugal direction and rotates in the opposite direction to the rotation direction (right), and the exit angle θ is formed to be smaller than 90 degrees.

The front end surface of each blade 10.10... is formed in a tapered shape that slopes backward with respect to the rotation axis, and the front end surface of each blade 10.10 has an annular rectifying plate 11 common to each blade.
is installed concentrically with the turbo fan 5.

Also, on the rear end surface of each blade 10.10 is an annular support 12.
It is fixed concentrically with the rotation axis.

A fixing part 8B having a bolt hole 8A is formed on the front surface of the base body 8, and its position is the same as the fixing screw hole 4A of the rotor 4. A bolt 6 is inserted into the bolt hole 8A and inserted into the fixing screw hole 4A. The turbo fan 5 is fixed to the rotor 4 by screwing together.

These turbo fans 5 have a base 8. Blade 10, annular current plate 11. The support body 12 is also made of plastic and manufactured by integral molding.

In the present invention having the above configuration, when the turbo fan 5 simultaneously rotates in the direction of the arrow as the rotor 4 rotates,
The outside air taken in from the intake lower A through the ducts 7B, 7B flows in the centrifugal direction on the inclined surface of the bulging portion 9, and is forced in the centrifugal direction by the centrifugal force by the blades 10.10. In this process, the airflow at the front end of each blade 10.10 slides into contact with the annular rectifying plate 11, is pushed toward the rear of the blade, and is rectified in the direction of the engine 1, increasing the flow velocity and increasing the flow rate, thereby enhancing the cooling effect. . That is, as shown in FIG. 4, when comparing the conventional type and the fan P of the present invention,
The flow 11Q of the present invention is larger with respect to the blade height D, and as a result, in order to obtain the same flow rate with the same diameter as the conventional type, it can be lowered by h, that is,
The blades can be lowered by that amount h, making it possible to downsize the entire fan.

In addition, because of the annular current plate 11, no vortex is generated between the front end surface of the blade 10 and the shroud 7, and as shown in the graph shown in FIG. 5, the sound pressure level is significantly reduced compared to the conventional fan. It can provide a low noise fan.

The present invention is not limited to the above configuration, and the design can be changed as appropriate.

〔Effect of the invention〕

The present invention has the following excellent effects.

A. Since an annular rectifying plate is provided on the front end surface of each blade, the airflow is rectified in the centrifugal direction, no vortex is generated between the blade front end surface and the shroud, noise is reduced, and the air flow speed is increased. The flow rate increases and the cooling effect improves.

B. As the flow rate increases, the height of the blades can be made lower or the diameter smaller than that of conventional fans, making it possible to downsize the entire fan and provide low noise for small space scooters etc. Can be equipped with a turbo fan.

[Brief explanation of drawings]

The drawings relate to the present invention; FIG. 1 is a sectional view of a turbo fan installed in the rotor of an alternator, FIG. 2 is a partial front view of the turbo fan, FIG. 3 is a sectional view of the turbo fan, and FIG. Figure 4 is a graph showing the relationship between blade height and air volume, Figure 5 is a graph showing the relationship between fan rotation speed and sound pressure level, and Figure 6 is a graph showing the relationship between fan rotation speed and sound pressure level.
The figure is a cross-sectional view of a conventional turbo fan. 1...Engine 2...Crankshaft 3...
・AC generator 4...Rotor 5...Turbo fan 7...Shroud 7A...Intake port
7B...Duct 8...Base 8A
...Bolt hole 8B...Fixing part 9...Bulging part 10...Blade 11...Annular current plate 12...Annular support patent applicant Riichi Honda Motor Co., Ltd.

Claims (1)

[Claims] An engine characterized in that a turbo fan is fixed concentrically to the tip of a rotor of a generator driven by the engine, and an annular baffle plate is installed on the front end surface of each blade concentrically with the rotation axis of the turbo fan. cooling turbo fan.